Improvement in the manufacture of cast-steel



UNITED STATES PATENT OFFICE.

P. G. GABDINEB, OF NEW YORK, N. Y.

IMPROVEMENT IN THE MANUFACTURE OF CAST-STEEL.

Specification forming part of Letters Patent No. 22,864, dated February 8, 1859'.

To all whom it may concern.-

Be it known that I, PERRY G. GARDINER, of the city of New York, in the State of New York, mechanical engineer, have discovered and invented a new and useful process for the treatment of cast-steel while passing from the molten to the hardening condition for the purpose of making unmanufactured ingots or other unmanufactured forms of steel of a peculiarly soft, tough,and malleable quality; andIhereby declare that the following is a full and exact description of my said process and of the man'- ner of performing and practicing the same.

I first prepare my molds formaking the ingots, bars, or other shapes, as may be desired, of fire-clay, black-lead, or any suitable material or composition which will not adhere to the melted metal and which will stand the intense heat to which they are to be subjected. These molds are then heated to an intense degree of heat, nearly equal to that at which the steel melts, and in this state of the molds the melted metal is poured into the molds; and it must be kept in the molds heated to this very high degree of heat, and in the oven or furnace a considerable time-say from six to eight hours-and after this let the heat of the molds slowly and gradually subside until the steel in them has fairly congealed and is at a cherryred heat. Then remove the steel expeditiously from the molds and immerse it immediately in a cistern of olive or whale oil heated to from 600 to 700 Fahrenheit, and it the ingots or bars are more than an inch in thickness the oil must be kept at this high degree of heat for ,several hours, and then permitted to become gradually quite cold. When the ingots or bars are less than an inch in thickness they need not be kept so long a time in the heated oil. By this process a very great degree of toughness, softness, and ductility is imparted to the steel. The less heated the oil is when the steel is immersed in it the harder will be the steel, but at the same time less tough andmalleable.

The nature of my discovery and invention does not consist in the gradual and prolonged cooling of the metal after melting for the purpose aforesaid; but it consists in the process of pouring the meltedmetal into intenselyheated molds and placing them immediately into the heated oven or furnace, then to cool and congeal away from the external atmosphere to a cherry-red heat, and then immediately plungingthcingotsorbars into thehighlyheated oil and retaining them immersed in it for a considerable period, as described.

In heating oil'to the high temperature above mentioned for the immersion of the steel, the vessel containing it and for heating should be provided with a movable close cover to prevent the escape of vapor and the danger of burning; and in all cases it is better to use a large quantity of oil for immersion of the steel.

The oven or furnace in whichthe melted steel is placed after being poured into the molds should be closed, and the flame or burning fuel 1 must not come in contact with the metal, but only the heat. 1

What I claim as my discovery and invention in the foregoing-described process is not simply the gradual and prolonged cooling of the metal after melting, as aforesaid, but it is the process as a whole of pouring the melted metal into intensely-heated molds,and then placing them thus filled immediately into the,

heated oven or furnace, then to congeal away from the external atmosphere down to a cherry-red heat, and then immediately plunging the ingots or bars into the highly-heated oil and retaining them immersed ill it for a com siderable time, as described.

P. G. GARDINER.

Witnesses:

J. B. STAPLE, GEORGE H. FOX. 

